01 A4 Avant Driveshaft replacement

[S P SHERMAN]

I am looking at the possible purchase of the subject line car, and the one serious problem with it is that it has a bad driveshaft vibration over ~3000RPM in the lower gears.
 
I was just curious what I might be getting into repair wise for this sort of thing. Can the shaft/bearings be reconditioned or replaced? Or is one looking at putting in an entire new driveshaft?

Any thoughts on that this would end up running, at a shop and if I can get the parts and do it myself (if this is a DIY type job).
 
Thanks